Broadband unidirectional uhf television antenna



Sept- 8, 1964 D. R. HOVERMAN 3,148,371

BROADBAND UNIDIRECTIONAL UHF TELEVISION ANTENNA Filed May 31, 1962 2Sheets-Sheet l /5 F's Z6 43 82 8 .?6a, 0 135 so if so V.

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BROADBAND UNIDIRECTIONAL UHF TELEVISION ANTENNA Filed May 51, 1962-3.5hee1zs-Sheet 2 fin 6126 0;"! 50 50 6 27/0 var/val;

United States Patent 3,148,371 BRGADBAND UNIDIRECTIONAL Um TELEVEIONANTENNA Doyt R. Hover-man, 925 Haley St., Van Wert, Ohio Filed May 31,1962, Ser. No. 198,855 9 Claims. (C1. 343-896) The present inventionrelates to a television-receiving antenna, and more particularly to aunitary antenna construction having broad frequency and unidirectionalresponse in the UHF television spectrum.

Commercim television signals are telecast in the frequency spectrumnormally characterized as ultra High Frequency. This spectrum iscommonly referred to in an abbreviated form as UHF. The UHF spectrumextends from 470 to 890 megacycles.

The present invention is particularly useful in this UHF spectrum andconstitutes an improvement in the antenna covered by my Patent No.2,918,672, issued Dec. 22, 1959. Experimentation and use of the antennaof my aforementioned patent has revealed that it possesses considerablegain both bidirectionally and omnidirectionally, depending upon thespecific construction used. However, the present invention is animprovement over the antenna of my prior patent in the respect that itis unidirectional and provides a substantial increase in gain over arela tively broad section of the UHF band.

It is therefore an object of this invention to provide a broadband,unidirectional antenna for use in the UHF spectrum, which exhibitssubstantial gain characteristics and can therefore be used in fringe,television areas.

It is another object of this invention to provide, in a singleconstruction, an antenna of simple and lightweight design which utilizesa coplanar driven array and a coplanar, resonant reflective array, thesetwo arrays being spaced apart and arranged in parallel planes.

The above-mentioned and other features and objects of this invention andthe manner of attaining them will become more apparent and the inventionitself will be best understood by reference to the following descriptionof an embodiment of the invention taken in conjunction with theaccompanying drawings, wherein:

FIGS. 1, 2 and 3 are perspective illustrations of three differentembodiments of this invention;

FIG. 4 is a side elevation of the antenna of FIG. 2; and

FIG. 5 is a fragmentary rear elevation of the antenna of FIG. 2.

Referring to the drawings, the driven element of the antenna showntherein may be constructed identically to that disclosed in FIG. 1 of myprior Patent No. 2,918,672 and described in the specification. Moreparticularly, and referring to FIG. 1, the driven element comprises twoelongated, metallic rod or wire-like elements 113 and 12. These twomembers or antenna sections and 12 are substantially identical,therefore the description of one will sufiice for both.

Each antenna section or wire-like member 10, 12 is bent into a series ofV-shaped elements, as indicated respectively by the reference numerals14, 16 and 18. Each of these V-shaped elements 14, 16, 18 have outwardlyextending legs 29, 22, 24, 26, 28 and 30, which are joined together,end-to-end, to provide three apices 32, 34 and 36 along one side and twoapices 38 and 40 along the other side. The apices 32, 34 and 36 aredisposed along a substantially straight imaginary line, as are the twoapices 38 and 4% along another substantially straight imaginary line,these two imaginary lines being substantially parallel. On theextremities of the two endmost legs and 30 are formed or integrallyconnected two substantially straight extensions 42 and 44, theseextensions being at substantially right angles to the two imaginarylines just described and, further, extending at obtuse angles withrespect to the respective legs 20 and 3%.

As shown in FIG. 1, the two antenna sections 10 and 12 are assembled insubstantial parallelism and in a common plane. Further, the endextensions 42, 44 are disposed to project oppositely to the endextensions 42a and 44a, respectively, the letter suffixes on thereference numerals indicating the same element on the antenna section 12as appears on the antenna section 10 which bears the same numeral.Further, these sections 10 and 12 are positioned with the respectiveapices 32, 34 and 36 juxtaposed and spaced from the respective apices32a, 34a and 35a.

Three bar-like nsulators formed of Plexiglas or polystyrene, 46, 48 and50, are fastened to the respective pairs of apices 32, 32a through 36,36a. Any suitable fastening means may be used, suitable bolts, nuts andwashers, as indicated by the reference numeral 52, being illustrated.Each individual apex 32 through 36 is clamped into a conformed groove inthe insulator under the head of the bolt 52, the bolt passing throughthe insulator and receiving on the other side a nut and washer. By meansof this fastening, the two antenna sections 10 and 12 are secured inassembled relation, but are electrically insulated from each other.

Experimentation has revealed that broadband operating characteristicsfor the reception of UHF television stations are achieved when theangles of all the apices 32 through 40 are substantially while thelengths of the legs 29 through 36 and the extensions 42 and 44 aresubstantially seven inches. When constructed according to thesedimensions, the antenna exhibits good performance even in Class B fringeareas for channels 14 through 35 in the UHF spectrum. The antenna isinstalled in an upright position as shown in FIGS. 1-3 inclusive; thatis, with the extensions 42, 42a, 44 and 44a extending horizontally.

While the angle of the individual apices 32 through 40 may be somethingother than 90, experiments have shown that either enlarging or reducingthe size of the angle affects the frequency response, causing theantenna to resonate at other points in the frequency spectra. If theseangles are made too large or too small, the antenna becomes inoperative.

A conventional two-conductor 300-ohm transmission line may be connectedto the driven element by fastening the ends of the two conductors to thetwo terminals 52 which are attached to the insulator 48.

A coplanar, resonant reflector screen is disposed to one side, or inother words the rear, of the driven element 10, 12 in parallelismtherewith. This reflector screen comprises an elongated supporting bar54- which may be fabricated of aluminum tubing or angle stock. Twotransverse supporting bars 56 are secured rigidly at one end thereof tospaced-apart points on the supporting bar 54 arid at the other ends tothe two insulators 46 and 59, this connection thereby electricallyinsulating the driven element 10, 12 from the reflector screen.

Mounted on the supporting bar 54 in spaced-apart relation are fourresonant reflector elements indicated generally by the referencenumerals 58, 6t), 62 and 64. Since the construction of these fourreflector elements is identical except for specific dimensioning whichwill be explained in more detail hereinafter, a description of one willsuflice for all. Referring more particularly to FIG. 5, the reflectorelement 58 is shown as comprising two colinear, elongated sections 66and 68 which may be fabricated of suitable aluminum tubing or bar stock.The adjacent ends of these two sections 66 and 68 are fitted into agroove 79 formed in a plastic insulating block 72,

suitaole screws 74 being used to secure the sections 66 and 68 to theblock 72. It should be noted that the adjacent ends of the two sections66 and 68 are spaced apart such that they will be electrically insulatedfrom each other and also from the supporting bar 54. A suitable screw 76passing through the central portion of the insulator 72 anchors thereflector element to the supporting bar 54.

As clearly shown in FIGS. 4 and 5, the reflector element 58 is mountedon a supporting bar 54 at right angles thereto and substantiallydirectly behind and in parallelism with the extensions 42 and 42a of thedriven element. In other words, the colinear reflector sections 66 and68 as well as the extensions 42 and 42a may be said to lie in a planewhich is perpendicular to the parallel planes of the driven element 10,12 and the reflector screen respectively.

Similarly, the reflector element 64, which preferably is identical inconstruction and size to the reflector element 58, is positioneddirectly behind and in parallelism with the lower driven elementextensions 44 and 44a.

The reflector element 66 is located immediately behind the two apices 38and 38a of the driven element, or in other words is located in a planepassing through the two apices 38 and 38a and which is perpendicular tothe plane of the driven element. The reflector element 62 is similarlypositioned with respect to the two apices 40 and 46a.

As already stated, the two reflector elements 58 and 64 are preferablyof the same construction and size. With respect to the two elements 66and 62, these are also identical to each other but, in the preferredembodiment of this invention, are somewhat shorter than the two elements58 and 60. For example, the reflector sections 66 and 68 of the tworeflector elements 58 and 60 are of equal length to each other, thislength being equal to a half-wavelength in the lower portion of the UHFspectrum. A typical dimension for each of the elements 66 and 68 isfourteen (14) inches. With respect to the individual sections for thereflector elements 60 and 62, these are selected as having a lengthequal to a half-wavelength in the upper region of the UHF spectrum, adimension of ten (10) inches being an example.

By locating the particular reflector elements as just described withrespect to the particular structural features of the driven element 10,12 the complete antenna exhibits a broadband frequency response in theUHF spectrum as well as unidirectional response. Also, the antennaexhibits an appreciable 'front-to-back gain ratio.

The antenna of FIG. 1 differs from the embodiment just described andillustrated in FIGS. 2, 4 and 5 in the respect that instead of usingcolinear resonant reflector elements 58, 60, 62 and 64, reflector bars78, 80, 82 and 84 are used. These particular reflector bars are ofunitary construction and preferably are fabricated of aluminum tubing,each bar being rigidly and electrically connected at its center to thesupporting bar 54 by means of suitable screw assemblies or the like.These reflector bars are positioned with respect to the driven elementthe same as the reflector elements 58, 60, 62 and 64 just described.

In the embodiment shown in FIG. 1, the two bars 78 and 84 are of thesame length, being equal to one or more odd numbers of wavelengths inthe lower portion of the UI-IF spectrum. Similarly, the two reflectorbars 89 and 82 have wavelengths equal to one or more odd numbers ofwavelengths in the upper regions of the UHF spectrum.

With respect to FIG. 3, the antenna there illustrated is shown as havinga reflector screen which is a composite of the screens shown in FIGS. 1and 2. With the same driven element 10, 12 as before, in this embodimentthe reflector screen is composed of two reflector bars 78 and 84 and twointermediate reflector elements 60 and 62. In all other respects, thisantenna is the same as that already shown and described in connectionwith FIGS. 1 and 2.

Experience has shown that the antenna of FIG, 2 is more eflicient over abroader frequency spectrum than the antenna of FIG. 1. Also, thedimensions as to the specific operating embodiments of this inventionwith respect to use in the lower portion of the UHF spectrum, that ischannels 14 to 35, may be appropriately scaled down if the antenna is tobe used in the upper regions of the UHF spectrum, that is above channel35, if it is desired to obtain maximum gain and efficiency in theseupper regions. In fact, experimentation has proven that in designing anantenna of this invention, the lengths of the various legs, such as 20,22, 24, 26, 23 and 30, may be calculated to be seventeen percent (17%)longer than'a quarter wavelength of the frequency of the lowest channelon which operation is desired. With respect to the reflector screen, inthe embodiment of FIG. 1, the upper and lower elements 78 and 84 arecalculated to have a length of twenty percent (20% longer than awavelength at the frequency of the lowest channel of operation and themiddle two elements 86 and 82 are calculated to have a length twentypercent (20%) longer than a wavelength at the frequency of the uppermostchannel of operation, such that if the antenna is designed to operate inthe range of channels 14 to 35, the elements 78 and 84 will have alength of about twenty-nine (29) inches and the elements 80 and 82 willhave a length of about twenty-four (24) inches. For the design of FIG.2, the element halves 66 and 68 are calculated to have a length eachwhich is seventeen percent (17%) longer than a half wavelength at thefrequency of the lowest channel of operation, and the halves of themiddle two elements 60 and 62 are calculated to have a length each whichis equal to one-half wavelength of the frequency of the uppermostchannel of desired operation. Thus, for a frequency spread from channels14 to 35, the halves 66 and 68 have a length of fourteen (14) inches andthe halves of the elements 60 and 62 have a length of ten (10) inches,respectively.

An antenna design to cover the frequency spread between channels 35 and58 will have dimensions correspondingly shorter than the specific onesjust given as will a third antenna design for the spread betweenchannels 58 and 83 have still correspondingly shorter dimensions.

In a typical operating embodiment of this invention, the separationbetween the planes of the driven element It), 12 and the reflectorscreen is in the order of three and one-half (3 /2) inches, thisparticular spacing providing relatively high gain over a relativelybroad portion of the UHF spectrum. Also, in a typical working embodimentof this invention, the foliowing materials and dimensions may be used inthe driven element 10, 12 it being understood that by giving thisexample the scope of the invention is not to be limited thereto but isto be determined by the coverage of the claims appended hereto.

Antenna sections 10, 12No. 9 hardened aluminum wire Insulators 46, 48,50 and 72Plexiglas or polystyrene, 2% inches by 1 to 1% inches with thetwo holes for the bolts 52 being spaced about 1% inches apart While Ihave described above the principles of my invention in connection withspecific apparatus, it is to be clearly understood that this descriptionis made only by Wayof example and not as a limitation to the scope of myinvention.

What is claimed is:

1. A broadband UHF unidirectional antenna comprising two side-by-side,coplanar, metallic antenna sections formed of rod-like material, saidtwo sections being of substantially identical configuration; eachsection comprising three series-connected V-shaped elements arranged inend-to-end relation thereby providing three, spacedapart apices alongone side and two spaced apart apices along the other side, said threeapices being disposed on a first imaginary substantially straight line,said two apices being disposed on a second imaginary substantiallystraight line which is substantially parallel to said first straight t0,the extremities of the two endmost V-shaped elements,

respectively, and extending away from both of said imaginary lines, theangles separating the V-shaped elements and the angles in the V-shapedelements themselves being substantially ninety degrees, the anglebetween said extensions and said second imaginary line beingsubstantially ninety degrees; said two antenna sections being spacedapart in parallelism with the three apices thereof being respectivelyjuxtaposed and lying on respective lines at right angles with respect tosaid imaginary lines, thereby providing three pairs of adjacent butspaced apart apices, three spaced apart bar-like insulators, said threepairs of apices being secured to said three insulators respectively; thelegs of said V-shaped elements and said extensions being approximatelyseven inches long, two terminals connected to the intermediate pair ofapices for attaching a dual conductor transmission line thereto, anelongated supporting bar lying in a plane which is normal to the planeof said antenna sections and which intersects the latter plane in a lineparallel to and midway between said first imaginary lines, said barbeing parallel to the plane of said antenna sections, two supportingelements having opposite ends, one end of each supporting element beingrigidly connected to the outermost ones respectively of said insulatorsand the other end of each element being rigidly connected to saidsupporting bar; a resonant planar reflector screen mounted on saidsupporting bar and lying in a plane parallel to said antenna sections,said screen comprising four rod-like reflector elements which areparallel to each other and extending at right angles to said supportingbar, two of said reflector elements being disposed directly behind theopposite end extensions of said antenna sections, respectively, theother two of said reflector elements being spaced apart and directlybehind two pairs of outermost apices of said antenna sections,respectively, each reflector element comprising two equal lengthsections having adjacent ends which are insulated from each other, foursupporting insulators, one support ing insulator each mounting each pairof adjacent reflector section ends onto said supporting bar, thereflector sections of the first-mentioned two reflector elements beingabout fourteen inches long, and the reflector sections of thesecond-mentioned two reflector elements being about ten inches long, thereflector screen being about three and one-half inches from the plane ofsaid antenna sections.

2. A broadband UHF unidirectional antenna comprising two side-by-side,coplanar, metallic antenna sections formed of rod-like material, saidtwo sections being of substantially identical configuration; eachsection comprising three series-connected V-shaped elements arranged inend-to-end relation thereby providing three, spacedapart apices alongone side and two spaced apart apices along the other side, said threeapices being disposed on a first imaginary substantially straight line,said two apices being disposed on a second imaginary substantiallystraight line which is substantially parallel to said first straightline, two parallel straight extensions integrally connected to theextremities of the two endmost V-shaped elements, respectively, andextending away from both of said imaginary lines, said two antennasections being spaced apart in parallelism with the three apices thereofbeing respectively juxtaposed and lying on respective lines at rightangles with respect to said imaginary lines, thereby providing threepairs of adjacent but spaced apart apices, three spaced apart bar-likeinsulators, said three pairs of apices being secured to said threeinsulators respectively; two terminals connected to the intermediatepair of apices for attaching a dual conductor transmission line thereto,an elongated supporting bar lying in a plane which is normal to theplane of said antenna sections and which intersects the latter plane ina line parallel to and midway between said first imaginary lines, saidbar being parallel to the plane of said antenna sections, two supportingelements having opposite ends, one end of each supporting element beingrigidly connected to the outermost ones respectively of said insulatorsand the other end of each element being rigidly connected to saidsupporting bar; a resonant planar reflector screen mounted on saidsupporting bar and lying in a plane parallel to said antenna sections,said screen comprising four rodlike reflector elements which areparallel to each other and extending at right angles to said supportingbar, two of said reflector elements being disposed directly behind theopposite end extensions of said antenna sections, respectively, theother two of said reflector elements being spaced apart and directlybehind two pairs of outermost apices of said antenna sections,respectively, each reflector element comprising two equal lengthsections having adjacent ends which are insulated from each other, foursupporting insulators, one supporting insulator each mounting each pairof adjacent reflector section ends onto said supporting bar, thereflector sections of the firstmentioned two reflector elements having alength about twenty percent longer than a half-wave in the lowerfrequency portion of the UHF spectrum, and the reflector sections of thesecond-mentioned two reflector elements having a length about twentypercent longer than a halfwave in the upper frequency portion of the UHFspectrum.

3. A broadband UHF unidirectional antenna comprising two side-by-side,coplanar, metallic antenna sections formed of rod-like material, saidtwo sections being of substantially identical configuration; eachsection comprising three series-connected V-shaped elements arranged inend-to-end relation thereby providing three, spacedapart apices alongone side and two spaced apart apices, along the other side, said threeapices being disposed on a first imaginary substantially straight line,said two apices being disposed on a second imaginary substantiallystraight line which is substantially parallel to said first straightline, two parallel straight extensions integrally connected to theextremities of the two endmost V-shaped elements, respectively, andextending away from both of said imaginary lines, said two antennasections being spaced apart in parallelism with the three apices thereofbeing respectively juxtaposed and lying on respective lines at rightangles with respect to said imaginary lines, thereby providing threepairs of adjacent but spaced apart apices, three spaced apart bar-likeinsulators, said three pairs of apices being secured to said threeinsulators respectively; two terminals connected to the intermediatepair of apices for attaching a dual conductor transmission line thereto,an elongated supporting bar lying in a plane which is normal to theplane of said antenna sections and which intersects the latter plane ina line parallel to and midway between said first imaginary lines, saidbar being parallel to the plane of said antenna sections, two supportingelements having opposite ends, one end of each supporting element beingrigidly connected to the outermost ones respectively of said insulatorsand the other end of each element being rigidly connected to saidsupporting bar; a resonant planar reflector screen mounted on saidsupporting bar and lying in a plane parallel to said antenna sections,said screen comprising four rod-like reflector elements which areparallel to each other and extending at right angles to said supportingbar, two of said reflector elements being disposed directly behind theopposite end extensions of said antenna sections, respectively, theother two of said reflector elements being spaced apart and directlybehind two pairs of outermost apices of said antenna sections,respectively, said supporting bar being conductive and said reflectorelements being connected thereto midway between the ends thereof, thefirst-mentioned two reflector elements each having a length about twentypercent longer than a full-wave length in the lower portion of the UHFspectrum, and the second-mentioned two reflector elements each having alength about twenty percent longer than a full-wave length in the upperportion of the UHF spectrum.

4. A broadband UHF unidirectional antenna comprising two side-by-side,coplanar, metallic antenna sections formed of rod-like material, saidtwo sections-being of substantially identical configuration; eachsection comprising three series-connected V-shaped elements arranged inend-to-end relation thereby providing three, spacedapart apices alongone side and two spaced apart apices along the other side, said threeapices being disposed on a first imaginary substantially straight line,said two apices being disposed on a second imaginary substantiallystraight line which is substantially parallel to said first straightline, two parallel straight extensions integrally connected to theextremities of the two endmost V-shaped elements, respectively, andextending away from both of said imaginary lines, said two antennasections being spaced apart in parallelism with the three apices thereofbeing respectively juxtaposed and lying on respective lines at rightangles with respect to said imaginary lines, thereby providing threepairs of adjacent but spaced apart apices, three spaced apart bar-likeinsulators, said three pairs of apices being secured to said threeinsulators respectively; two terminals connected to the intermediatepair of apices for attaching a dual conductor transmission line thereto,an elongated supporting bar lying in a plane which is normal to theplane of said antenna sections and which intersects the latter plane ina line parallel to and midway between said first imaginary lines, saidbar being parallel to the plane of said antenna sections, two supportingelements having opposite ends, one end of each supporting element beingrigidly connected to the outermost ones respectively of said insulatorsand the other end of each element being rigidly connected to saidsupportng bar; a resonant planar reflector screen mounted on saidsupporting bar and lying in a plane parallel to said antenna sections,said screen comprising four rod-like reflector elements which areparallel to each other and extending at right angles to said supportingbar, two of said reflector elements being disposed directly behind theopposite end extensions of said antenna sections, respectively, theother two of said reflector elements being spaced apart and directlybehind two pairs of outermost apices of said antenna sections,respectively, said supporting bar being conductive, the firstmentionedtwo reflector elements comprising two equal length sections havingadjacent ends which are insulated from each other, two supportinginsulators, one supporting insulator each mounting each pair of saidadjacent reflector section ends onto said supporting bar, the reflectorsections having a length about twenty percent longer than a half-wave inthe lower portion of the UHF spectrum, the second-mentioned tworeflector elements being connected midway between the ends thereof tosaid supporting bar, said second-mentioned reflector elements eachhaving a length about twenty percent longer than a half-Wave length inthe upper portion of the UHF spectrum.

5. A broadband UHF unidirectional antenna comprising two side-by-side,coplanar, metallic antenna sections formed of rod-like material, saidtwo sections being of substantially identical configuration; eachsection comprising an odd plurality of series-connected V-shapedelements arranged in end-to-end relation thereby providing a firstseries of spaced apart apices along one side and a second series ofspaced apart apices along the other side, each V-shaped elementincluding two leg portions, two parallel straight extensions connectedto the extremities of the two endmost V-shaped elements respectively,said extensions forming obtuse angles with said extremities,respectively; said two antenna sections being spaced apart inparallelism with the first series apices being respectively juxtaposedthereby providing plural pairs of adjacent but spaced apart apices, andmeans fixedly securing said antenna sections into assembled relation,the lengths of the leg portions of the V-shaped elements beingsubstantially equal and corresponding to a length about seventeenpercent greater than a quarter of a Wavelength at a selected frequencyin the UHF spectrum, an elongated supporting bar lying in a plane whichis normal to the plane of said antenna sections and which intersects thelatter plane in a straight line passing between said antenna sections,means securing said antenna sections to said sup porting bar; a resonantplanar reflector screen mounted on said supporting bar and lying in aplane parallel to said antenna sections, said screen comprising fourrod-like reflector elements which are parallel to each other andextending at right angles to said supporting bar, two of said reflectorelements being disposed directly behind the opposite end extensions ofsaid antenna sections, respectively, the other two of said reflectorelements being spaced apart and directly behind two pairs of outermostapices of said antenna sections, respectively, each reflector elementcomprising two equal length sections having adjacent ends which areinsulated from each other, four supporting insulators, one supportinginsulator each mounting each pair of adjacent reflector section endsonto said supporting bar, the reflector sections of the first-mentionedtwo reflector elements having a length about twenty percent longer thana half-Wave in the lower frequency portion of the UHF spectrum, and thereflector sections of the second-mentioned two reflector elements havinga length about twenty percent longer than a half-wave in the upperfrequency portion of the UHF spectrum.

6. A broadband UHF unidirectional antenna comprising two side-by-side,coplanar, metallic antenna sections formed of rod-like material, saidtwo sections being of substantially identical configuration; eachsection comprising an odd plurality of series-connected V-shapedelements arranged in end-to-end relation thereby providing a firstseries of spaced apart apices along one side and a second series ofspaced apart apices along the other side, each V-shaped element havingtwo leg portions, two parallel straight extensions connected to theextremities of the two endmost V-shaped elements respectively, saidextensions forming obtuse angles with said extremities, respectively;said two antenna sections being spaced apart in parallelism with thefirst series apices being respectively juxtaposed thereby providingplural pairs of adjacent but spaced apart apices, and means fixedlysecuring said antenna sections into assembled relation, the lengths ofthe leg portions of the V-shaped elements being substantially equal andcorresponding to a length about seventeen percent greater than a quarterof a wavelength at a selected frequency in the UHF spectrum, anelongated supporting bar lying in a plane which is normal to the planeof said antenna sections and which intersects the latter plane in astraight line passing between said antenna sections, means securing saidantenna sections to said supporting bar; a resonant planar reflectorscreen mounted on said supporting bar and lying in a plane parallel tosaid antenna sections, said screen comprising four rodlike reflectorelements which are parallel to each other and extending at right anglesto said supporting bar, two of said reflector elements being disposeddirectly behind the opposite end extensions of said antenna sections,respectively, the other two of said reflector elements being spacedapart and directly behind two pairs of outermost apices of said antennasections, respectively, said supporting bar being conductive and saidreflector elements being connected thereto midway between the endsthereof, the first-mentioned two reflector elements each having a lengthabout twenty percent longer than a full wave length in the lower portionof the UHF spectrum, and the secondmentioned two reflector elements eachhaving a length about twenty percent longer than a full wave length inthe upper portion of the UHF spectrum.

7. A broadband UHF unidirectional antenna comprising two side-by-side,coplanar, metallic antenna sections formed of rod-like material, saidtwo sections being of substantially identical configuration; eachsection comprising an odd plurality of series-connected V-shapedelements arranged in end-to-end relation thereby providing a firstseries of spaced apart apices along one side snassvr and a second seriesof spaced apart apices along the other side, each t -shaped elem ntincluding two legs portions, two parallel straight extensions connectedto the extremities of the two endrnost t haped elements respectively,said extensions forming at obtuse angles with said extrerni ties,respectively; said two antenna sections being spaced apart inparallelism with the first series apices being respectively juxtaposedthereby providing plural pairs of adjacent but spaced apart apices, andmeans fixedly securing said antenna sections into assembled relation,the lengths of the leg portions of the V-shaped elements beingsubstantially equal and corresponding to a length about seventeeenpercent greater than a quarter of a wavelength at a selected frequencyin the UHF spectrum, an elongated supporting bar lying in a plane whichis normal to the plane of said antenna sections and which intersects thelatter plane in a straight line passing between said antenna sections,means securing said antenna sections to said supporting bar; a resonantplanar reflector screen mounted on said supporting bar and lying in aplane parallel to said antenna sections, said screen comprising fourrod-like reflector elements which are parallel to each other andextending at right angles to said supporting bar, two of said reflectorelements being disposed directly behind the opposite end extensions ofsaid antenna sections, respectively, the other two of said reflectorelements being spaced apart and directly behind two pairs of outermostapices of said antenna sections, respectively, two of said reflectorelements having lengths equal to an odd number of wave lengths in thelower portion of the UHF spectrum, and two of said reflector elementshaving lengths equal to an odd number of wave lengths in the upperportion of the UHF spectrum,

8. The antenna of claim 7 wherein the spacing between the reflectorscreen and the plane of the antenna sections is equal to about one-sixthof a wavelength in the upper portion of the UHF spectrum.

9. A broadband UHF unidirectional antenna comprising two side-by-side,coplanar, metallic antenna sections formed of rod-like material, saidtwo sections being of substantially identical configuration; eachsection comprising an odd plurality of series-connected V-shapedelements arranged in end-to-end relation thereby providing a firstseries of spaced apart apices along one side and a second series ofspaced apart apices along the other side, each V-shaped elementincluding two leg portions, two parallel straight extensions connectedto the extremities of the two endmost V-shaped elements respectively,said extensions forming obtuse angles with said extremities,respectively; said two antenna sections being spaced apart inparallelism with the first series apices being respectively juxtaposedthereby providing plural pairs of adjacent but spaced apart apices, andmeans fixedly securing said antenna sections into assembled relation,the lengths of t e leg portions of the t -shaped elements beingsubstantially equal and corresponding to a length about seventeenpercent greater than a quarter of a Wave length at a selected frequencyin the UHF spectrum, a resonant plareilector screen, means for mountingsaid screen in a plane parallel to said antenna sections, said screencomprising a plurality of rod-like reflector elements which are spacedapart and parallel to each other and also transverse to an imaginaryline drawn between said first and second series of apices, at least oneof said reflector elements having a length about twenty percent longerthan a wave length at a selected frequency in the lower portion of theUHF spectrum and at least one of said reflector elements having a lengthabout twenty percent longer than a wave length at a selected frequencyin a higher portion r" the UHF spectrum.

References fits-d in the file of this patent U\lTED STATES lAT NTS

9. A BROADBAND UHF UNIDIRECTIONAL ANTENNA COMPRISING TWO SIDE-BY-SIDE,COPLANAR, METALLIC ANTENNA SECTIONS FORMED OF ROD-LIKE MATERIAL, SAIDTWO SECTIONS BEING OF SUBSTANTIALLY IDENTICAL CONFIGURATION; EACHSECTION COMPRISING AN ODD PLURALITY OF SERIES-CONNECTED V-SHAPEDELEMENTS ARRANGED IN END-TO-END RELATION THEREBY PROVIDING A FIRSTSERIES OF SPACED APART APICES ALONG ONE SIDE AND A SECOND SERIES OFSPACED APART APICES ALONG THE OTHER SIDE, EACH V-SHAPED ELEMENTINCLUDING TWO LEG PORTIONS, TWO PARALLEL STRAIGHT EXTENSIONS CONNECTEDTO THE EXTREMITIES OF THE TWO ENDMOST V-SHAPED ELEMENTS RESPECTIVELY,SAID EXTENSIONS FORMING OBTUSE ANGLES WITH SAID EXTREMITIES,RESPECTIVELY; SAID TWO ANTENNA SECTIONS BEING SPACED APART INPARALLELISM WITH THE FIRST SERIES APICES BEING RESPECTIVELY JUXTAPOSEDTHEREBY PROVIDING PLURAL PAIRS OF ADJACENT BUT SPACED APART APICES, ANDMEANS FIXEDLY SECURING SAID ANTENNA SECTIONS INTO ASSEMBLED RELATION,THE LENGTHS OF THE LEG PORTIONS OF THE V-SHAPED ELEMENTS BEINGSUBSTANTIALLY EQUAL AND CORRESPONDING TO A LENGTH ABOUT SEVENTEENPERCENT GREATER THAN A QUARTER OF A WAVE LENGTH AT A SELECTED FREQUENCYIN THE UHF SPECTRUM, A RESONANT PLANAR REFLECTOR SCREEN, MEANS FORMOUNTING SAID SCREEN IN A PLANE PARALLEL TO SAID ANTENNA SECTIONS, SAIDSCREEN COMPRISING A PLURALITY OF ROD-LIKE REFLECTOR ELEMENTS WHICH ARESPACED APART AND PARALLEL TO EACH OTHER AND ALSO TRANSVERSE TO ANIMAGINARY LINE DRAWN BETWEEN SAID FIRST AND SECOND SERIES OF APICES ATLEAST ONE OF SAID REFLECTOR ELEMENTS HAVING A LENGTH ABOUT TWENTYPERCENT LONGER THAN A WAVE LENGTH AT A SELECTED FREQUENCY IN THE LOWERPORTION OF THE UHF SPECTRUM AND AT LEAST ONE OF SAID REFLECTOR ELEMENTSHAVING A LENGTH ABOUT TWENTY PERCENT LONGER THAN A WAVE LENGTH AT ASELECTED FREQUENCY IN A HIGHER PORTION OF THE UHF SPECTRUM.